1. Field of the Invention
This invention relates generally to dispersing a volatilizable compound in an environment, and particularly relates to dispersing a heat-stable, volatile fragrance.
2. Background of the Invention
Dispersal of volatilizable compounds, through evaporation and/or vaporization, into an environment from a substrate or carrier has long been practiced for a variety of purposes. As early as 1876, British Pat. No. 3885 disclosed an improvement in the treating of tobacco comprising providing a permeable receptacle which enclosed and contained an efflorescent salt or a porous body, which salt or body was charged by the user with a compound which exudes either a liquid or vapor through the receptacle, which was placed in the smoker's pouch or tobacco jar. British Pat. No. 570,239 disclosed an efflorescent block for the controlled evolution and dissemination of ammonia into a surrounding body of gas, such as the atmosphere in a relatively confined space, which gradually crumbled and disintegrated so as to cause fresh areas of the block composition continuously to become exposed to the air, whereby a steady evolution of the ammonia was secured. Kelly, U.S. Pat. No. 3,371,984, disclosed a solid air odorizing composition in tablet form, for use in combination with a vacuum cleaner, which was "adapted to controllably release a pleasing odor." Claim 1. The tablet comprised a hydrated salt which irreversibly lost its water of hydration with which a fragrance was mixed, which composition was then compacted to the tablet form. Col. 2, line 66 -col. 3, line 5. The loss of water resulted in the slow crumbling or disintegration of the tablet, providing a fresh surface necessary for fragrance release of about four weeks duration in vacuum cleaner use. Example 2.
While these means for effecting dispersal of volatilizable compounds into an environment, e.g., a surrounding body of gas, such as the atmosphere in a relatively confined space, are thus kwown, they exhibit serious drawbacks. British Pat. No. 3885 requires the use of a two element combination of container and absorbant substrate, which must be charged with the volatilizable material by the user at the inception of use and, apparently, frequently thereafter. British No. 570,239 and Kelly U.S. Pat. No. 3,371,984 are unable to provide persistent, long-term dispersal of a volatilizable compound, particularly in an environment wherein the dispersing article is exposed to a gaseous flow, such as convective flow from a heat source or forced flow, such as from a forced-air furnace. Further, their mechanism resulting in the efflorescence, crumbling or disintegration of the substrate or carrier block creates a litter problem which is particularly troublesome in home or office. Finally, Kelly can provide no long-term, persistent release of volatilizable compound.
The optimum combination of properties for a method and article for dispersing volatilizable compounds in an environment would comprise:
(1) An article incorporating the volatilizable compound which requires no charging of said compound by the user at the inception of use or thereafter; PA0 (2) The article would be a solid, coherent article, rather than a granular or particulate substance, which could be utilized without need for an enclosing receptacle or container, such as is required for such a granular or particulate substance; PA0 (3) The article would remain solid and coherent throughout its useful life, and would not disintegrate, crumble, decompose or effloresce; PA0 (4) The article would provide persistent, long-term dispersal of the volatilizable compound in an environment; and PA0 (5) The article would further provide dispersal of the volatilizable compound in response to a gaseous flow in said environment, including convective and forced flow. PA0 from about 25 to 30 wt. % initially particulate calcium sulfate having a loose bulk density of from about 0.85 to 0.95 gm/cm.sup.3 ; PA0 about 25 to 30 wt. % initially particulate calcium sulfate having a loose bulk density of from about 0.70 to 0.75 gm/cm.sup.3 ; PA0 about 2 to 4 wt % initially particulate hydrous calcium sulfate having a loose bulk density of from about 0.75 to 0.85 gm/cm.sup.3 ; PA0 about 0.5 to 1 wt. % emulsifier; PA0 about 6 to 7 wt. % volatilizable compound; and PA0 about 30 to 35 wt. % water. PA0 (a) Combining from about 0.5 to 1 wt. % emulsifier and from about 6 to 7 wt. % of a volatilizable compound; PA0 (b) Agitating and mixing said combined emulsifier and volatilizable compound until a uniform emulsion is formed; PA0 (c) Combining with agitation the emulsion of step (b) with from about 30 to 35 wt. % water; PA0 (d) Adding with agitation from about 2 to 4 wt. % particulate hydrous calcium sulfate having a loose bulk density of from about 0.75 to 0.85 gm/cm.sup.3 to the mixture of step (c); PA0 (e) Adding with agitation to the mixture of step (d) from about 25 to 30 wt. % particulate calcium sulfate having a loose bulk density of from about 0.85 to 0.95 gm/cm.sup.3, and from about 25 to 30 wt. % particulate calcium sulfate having a loose bulk density of from about 0.70 to 0.75 gm/cm.sup.3 ; PA0 (f) Agitating the mixture of step (e) until a smooth slurry is formed; PA0 (g) Placing said slurry in a molding zone; and PA0 (h) Allowing said slurry to set in said molding zone until a solid article is formed. PA0 (1) a solid volatilizable compound consisting essentially of PA0 (2) package means slightly larger than said article, said means encasing said article, said means being sealed and being made of a flexible, tearable barrier film, which seals upon the application of heat and pressure, so that the envelope may be opened by being torn and being substantially unaffected by and substantially impermeable to said volatilizable compound and the vapors thereof, and being of a strength to resist the vapor pressure thereof.
None of the methods and articles for dispersing a volatilizable compound known to the art, however, provide this optimum combination of properties with respect to effecting such dispersal in an environment.